The answer should be 0.5 because 6/12 is 0.5. It gives u the key equation
Magnet to remove the iron, filter paper (or some filter that could trap sand) to remove the sand, and heat up the salt and water, causing the water to evaporate to separate them.
Balance the reaction first:
3KOH + H3PO4 —> K3PO4 + 3H2O
So for every mol of H3PO4, you need 3 mol of OH- to fully neutralize the acid, since H3PO4 is polyprotic.
0.0200 L KOH • (2.000 mol KOH / L KOH) • (1 mol H3PO4 / 3 mol KOH) = 0.0133 mol H3PO4
Divide this by the volume of H3PO4 to get the concentration.
0.0133 mol H3PO4 / 0.0250 L = 0.532 M H3PO4
